SettingsDialog: fix compiler warning
SettingsPage: remove Obsolete attribute from _loadingSettings, add property IsLoadingSettings.
ChecklistSettingsPage: fix compiler warning
ChecklistSettingsPage: remove obsolete property ChecklistSettingsPage and fix depending code
PluginSettingsPage: fix compiler warning
FormSettings: move the Checklist SettingsPage one level up.

The Checklist is now shown when the "Git Extensions" root node is selected.
(Before, selecting "Git Extensions" caused the treeview to "snap" to the first subnode)
FormSettings: add a Page with introductory text as the Plugin Settings root.
CreateTag dialog: cancel should not refresh the revision grid
CommitPickerSmallControl: SetSelectedCommitHash shows message box if manually entered commit hash is not correct
FormCheckoutRevision: make similar to CreateBranch/Tag dialogs. Do not refresh grid when user hits cancel.
RevisionGrid: use StartCheckoutRevisionDialog instead of simple message box
Rename IGitUICommands.StartCheckoutBranchDialog to .StartCheckoutBranch() because this method does not always show a dialog (see form.DoDefaultActionOrShow(owner))
Merge pull request #1683 from feinstaub/topic_settings_dlg

SettingsDialog: fix compiler warnings / put pages to the root nodes
Merge pull request #1685 from feinstaub/topic_norefresh_on_cancel

FormCheckoutRevision: make similar to CreateBranch/Tag dialogs and use in RevisionGrid
Variable name fixed
"Set version" Python script added
GetFullBranchName moved from GitModule to GitCommandHelpers

Commit renamed to CommitHelper