Code::Blocks SVN Repo

- Build: Remove boost::system detection (end of ticket #1563).
The NassiShneiderman plugin does not use it and now it is a header-only library,
so detection failed.

- avoid warnings from style checkers (no functional change)

- GUI: Do not use arithmetic operator &= with booleans.

- KeyBinder: Do not use arithmetic operator &= with booleans.

- ProjectOptionsManipulator: Do not use arithmetic operator &= with booleans.

- GUI: Do not use arithmetic operator &= with booleans.

* dragscroll: version 1/4/15 251020 Remember the original (current) mouse position for other events to use.

* BrowseTracker: Apply JumpTracker.h assert fix (Thanks Christo and Letartare)
See https://forums.codeblocks.org/index.php?topic=26149.msg177897#msg177897

- NassiShneiderman: Remove boost_system requirement from autotools (ticket #1563).
The plugin uses header-only boost libraries.

- NassiShneiderman: Do not link with unused boost_system library (ticket #1563).
The boost_system library has been removed in recent boost, now it is a header-only library and part of C++11.
Tested on Mint 18, tHe autotools part will come later.