Fix regression where creator was no longer able to run git if the
PATH was not explicitly set in the configuration.

Task-number: QTCREATORBUG-2478
Reviewed-by: Robert Loehning

Fix commiting with Author and Email set on Windows.

Task-number: QTCREATOR-2397

Reviewed-by: dt

In cases where binary 'wish' is not in PATH variable this could not be
started.

Also introduce a indirection, modes have now types, edit and debug have
the same type, and editors do have a prefered type of modes instead of a
prefered mode.

That fixes the bug that if the prefered qml editing mode was set to
design, then in switching between qml editors would
- in Edit Mode: stay in edit mode
- in Debug Mode: switch to debug mode

The function always switched to Edit Mode, which was the cause for
several bugs. Since openEditor() already does switch to the right mode,
the function is not really needed.

The following actions now respect the prefered mode of the editor:
"f file"-locator
The Open Documents list
Editor history navigation

Make GitClient::synchronousGit use the process environment.

Windows: Add a setting to fake a 'HOME' environment variable
(%HOMEDRIVE%%HOMEPATH%) to make msysgit look for its SSH-keys
there not only when run from git bash, but also from Qt Creator.
Useful in MinGw-setups, where git must not be in the path.

Task-number: QTCREATORBUG-1642

Update 'Commit' button to show number of files to be committed.
Task-number: QTCREATORBUG-2090

... for git, hg as it is not obvious from the SHA1 displayed.

Provide UI with manual refresh button in BaseCheckoutWizardPage.
Change ProcessCheckoutJob to be able to execute several steps.
Implement in git.

Task-number: QTCREATORBUG-1795

Task-number: QTCREATORBUG-1795

Reviewed-by: Friedemann Kleint

Reviewed-by: con

A mostly mechanical change.

Reviewed-By: con

Task-number: QTCREATORBUG-1577

Introduce extra flag.

Task-number: QTCREATORBUG-1623

Task-number: QTCREATORBUG-1577