Helps with disambiguating global functions, for example.

- clear up some Q_OS_LINUX vs. Q_OS_UNIX
- clear up Q_WS_* vs. Q_OS_* (relatively theoretical exercise)
- use proper #if-#else cascades instead of free-standing #ifs

HTML escaping was moved out of the TypePrettyPrinter since it interferes
with other logic there. Instead, the region to mark is now available
from the Overview and used by the FunctionArgumentWidget to put the
current argument in bold.

Was missing in commit efc0b208.

Reviewed-by: Roberto Raggi

Only attempt to activate the completion when there is a function id on
the left of the parenthesis.

Reviewed-by: Roberto Raggi

Since we're automatically inserting several kinds of brackets, but not
braces ({ }).

Putting Cpp file settings into a GroupBox

Make debugger tooltip API more general, have the engines check the
correct file type, figure out the expression and context from the text
editor.

Put common functionality in watchutils.cpp. In the CDB engine, check
whether a tooltip expression is a known variable within the stack frame
context. If so, retrieve via symbol group or dumpers. Cache by function
and expression.
Reviewed-by: hjk <qtc-committer@nokia.com>

As this is how it is navigated by keyboard.

Reviewed-by: con <qtc-committer@nokia.com>

This adds a way for plugins to tell the cppmodel that for certain files,
the actual contents come from it, instead of reading from the disk.
(For texteditors the cppmodel does that automatically.)

Reviewed-By: Roberto Raggi <roberto.raggi@nokia.com>