Add a GCancellable to EActivity.

EActivity now uses a GCancellable to manage cancellations, instead of
having its own redundant cancellation API.  API changes are as follows:

  + e_activity_get_cancellable()
  + e_activity_set_cancellable()

  - e_activity_cancel()
  - e_activity_is_cancelled()
  - e_activity_get_allow_cancel()
  - e_activity_set_allow_cancel()

EActivity's "cancelled" signal remains, but only as a repeater for
GCancellable::cancelled signals.  It should not be emitted directly.

The presence of a GCancellable implies that cancellation is allowed.
EActivity does not create its own default GCancellable, it has to be
given one.

If a CamelOperation (cast as a GCancellable) is given, EActivity will
configure itself to listen for status updates from the CamelOperation
and propagate the information to its own "primary-text" and "percent"
properties.

These changes allowed me to start cleaning up some of the incredibly
convoluted logic in mail-mt.c -- in particular, mail_operation_status()
is completely gone now.  mail-mt.c is still in a transitional state --
much more significant changes coming soon.

3 files changed, 37 insertions, 25 deletions

diff --git a/doc/reference/shell/eshell-sections.txt b/doc/reference/shell/eshell-sections.txt
index 05ac15878e..d8b8a5cbd5 100644
--- a/doc/reference/shell/eshell-sections.txt
+++ b/doc/reference/shell/eshell-sections.txt
@@ -461,14 +461,12 @@ EActionComboBoxPrivate
 EActivity
 e_activity_new
 e_activity_newv
-e_activity_cancel
 e_activity_complete
 e_activity_clicked
 e_activity_describe
-e_activity_is_cancelled
 e_activity_is_completed
-e_activity_get_allow_cancel
-e_activity_set_allow_cancel
+e_activity_get_cancellable
+e_activity_set_cancellable
 e_activity_get_clickable
 e_activity_set_clickable
 e_activity_get_icon_name
diff --git a/doc/reference/shell/tmpl/e-activity.sgml b/doc/reference/shell/tmpl/e-activity.sgml
index d56bd0776a..871758fb5e 100644
--- a/doc/reference/shell/tmpl/e-activity.sgml
+++ b/doc/reference/shell/tmpl/e-activity.sgml
@@ -31,7 +31,7 @@ e-activity
 
 </para>
 
-@primary_text: 
+@void: 
 @Returns: 
 
 
@@ -45,14 +45,6 @@ e-activity
 @Returns: 
 
 
-<!-- ##### FUNCTION e_activity_cancel ##### -->
-<para>
-
-</para>
-
-@activity: 
-
-
 <!-- ##### FUNCTION e_activity_complete ##### -->
 <para>
 
@@ -78,15 +70,6 @@ e-activity
 @Returns: 
 
 
-<!-- ##### FUNCTION e_activity_is_cancelled ##### -->
-<para>
-
-</para>
-
-@activity: 
-@Returns: 
-
-
 <!-- ##### FUNCTION e_activity_is_completed ##### -->
 <para>
 
@@ -96,7 +79,7 @@ e-activity
 @Returns: 
 
 
-<!-- ##### FUNCTION e_activity_get_allow_cancel ##### -->
+<!-- ##### FUNCTION e_activity_get_cancellable ##### -->
 <para>
 
 </para>
@@ -105,13 +88,13 @@ e-activity
 @Returns: 
 
 
-<!-- ##### FUNCTION e_activity_set_allow_cancel ##### -->
+<!-- ##### FUNCTION e_activity_set_cancellable ##### -->
 <para>
 
 </para>
 
 @activity: 
-@allow_cancel: 
+@cancellable: 
 
 
 <!-- ##### FUNCTION e_activity_get_clickable ##### -->
diff --git a/doc/reference/shell/tmpl/eshell-unused.sgml b/doc/reference/shell/tmpl/eshell-unused.sgml
index 15c9658da6..59aed5d191 100644
--- a/doc/reference/shell/tmpl/eshell-unused.sgml
+++ b/doc/reference/shell/tmpl/eshell-unused.sgml
@@ -95,6 +95,37 @@ e-shell-window.sgml
 
 @window: 
 
+<!-- ##### FUNCTION e_activity_cancel ##### -->
+<para>
+
+</para>
+
+@activity: 
+
+<!-- ##### FUNCTION e_activity_get_allow_cancel ##### -->
+<para>
+
+</para>
+
+@activity: 
+@Returns: 
+
+<!-- ##### FUNCTION e_activity_is_cancelled ##### -->
+<para>
+
+</para>
+
+@activity: 
+@Returns: 
+
+<!-- ##### FUNCTION e_activity_set_allow_cancel ##### -->
+<para>
+
+</para>
+
+@activity: 
+@allow_cancel: 
+
 <!-- ##### FUNCTION e_get_user_data_dir ##### -->
 <para>