Increment version to 2.1.0

Increase version to 2.0.0

Update version to 1.3.2

Update version to 1.3.1

Update README and manual

Updated version to 1.2.3

Updated version to 1.2.2

Updated version to 1.2.1

Replaced concatenation of directory + filename strings with Glib::bui…

…ld_filename

Changes from v1.1.4-git20120702

 * Added integrated autoleveller (idea taken from [here](https://www.autoleveller.co.uk/)) - **EXPERIMENTAL** (and **UNTESTED** on Mach3, Mach4 and TurboCNC)
 * Added _--optimise_ option (can reduce the output gcode size up to 95%)
 * Added bridges on outline cut
 * Added preamble and postable inputs
 * Added preamble-text input (ex. for license file)
 * Added custom G64
 * Added a switch to substitute G81 with G0 + G1 (_--nog81_)
 * Added _--cut-front_ option
 * Added _--zero-start_ option
 * Added _--output-dir_ option
 * Added M5 at the end of the gcode
 * Multiple fixes on boolean command line options
 * Fixed wrong computation of board margin when _--extra-passes_ is enabled
 * Fixed  _--milldrill_ and _--mill-front_ bug