Debugger: Fix race condition

When getting debugger finished after a device disconnect it might
re-enable the 'Start Debugging' button although debugging is
not possible.

Task-number: QTCREATORBUG-12585
Change-Id: I8901b440bb3e90e5f29cdeba2f6629d157c2e335
Reviewed-by: hjk <hjk121@nokiamail.com>
C++: fix include/framework path handling.

Instead of having two lists of paths, now only one list is used where
both include paths and framework paths can be mixed. This reflects the
way the compiler is invoked, and retains the (correct) search order.

Task-number: QTCREATORBUG-11599
Change-Id: I373953e3e305df5b7a0d10920e12d146584adf9f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Bookmark: Save after internal changes

Task-number: QTCREATORBUG-10687
Change-Id: Ie2cb0b990d7dd419f27469612cb422e55e7d322f
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
CppEditor: Check for a valid document

...from the semantic info before trying to use it.

Just after opening a file and using Follow Symbol the semantic document
might not be yet calculated.

Change-Id: I62deaf86415a2e2b0d7f1285f90bdcd9b5925a2e
Reviewed-by: Nikita Baryshnikov <nib952051@gmail.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>