* Centralize the error message text shown to the user in the event of a problem
installing the update in AppInfo::updateErrorMessage() and add a section
suggesting that the user should download a new copy from mendeley.com
Build the GTK dialog as a separate shared library which
is embedded into the main updater binary.
At runtime the updater extracts the shared library and attempts to load it.
If this succeeds, the GTK UI is used, otherwise the updater will fall
back to something else - currently a silent install.
The current update dialogs do not support retry/cancel - if a file
cannot be installed the update will just fail with an error and
any partial install will be reverted.
* Fix ProcessUtils::runAsyncUnix() not returning a value
* Fix UpdateDialogGtk::updateRetryCancel() not returning a value
* Add missing includes in TestUpdaterOptions.cpp
* Fix unsigned/signed int comparisons
* Add optional GTK mode to the updater build. This pulls in a large number of extra dependencies,
but dependencies which should be fairly ubiquitous on Linux systems. If these dependencies prove
to be a problem we could look at providing an alternative, more basic UI and loading the appropriate
UI dynamically.
* Implement update progress dialog for GTK. The dialog needs visual polish but is functional.
