cmder: Default bash tasks in ConEmu don't work in mini installations

@daxgames While documenting this issue in README is an acceptable alternative to fixing a problem that we’re sure not a lot of people might occur, I think it’s still a better solution to try and fix it IF a) the fix is easy and b) it doesn’t break other parts of Cmder.

Regarding in naming it cmder bash I’d say it would be an appropriate name because the way cmder currently handles it is by only calling vendored Git’s bash.

This is acceptable behavior to many users of Cmder, and this issue can be closed. However, I’d like to ask to write a fix for it, by changing a small portion of Cmder logic: creating the ConEmu.xml based on user machine’s configuration. That way a better (an easier) integration between Cmder and external shells installed on user’s machine is guaranteed.

@Stanzilla that’d also make sense,

• if Git is not found don’t initialize it
• if bash is selected but not found, show sensible error
• on first launch if mini version, remove bash from tasks

That way we’d avoid this issue on fresh installs, and won’t introduce breaking changes to previous installs by displaying an appropriate message.

@Stanzilla is %GIT_INSTALL_ROOT% a cmder-specific env var? I always get confused by this one because it sounds like it is set by git-for-windows. I expected it to be called something like %cmder_git_root% if it was set by cmder.