Fix bug in UndoBuffer with TextViewer

Adding support for selecting user data type for function return type

Adding support for coloring following elements:
- STRING constants
- Data type in typed literals
- Function and functionBlock parameter names

Fix bug with TRUNC function and with type conversion functions called with constant as parameter

Fixing REAL_TO_INT conversion (behaved like a trunc and not like a round)

Fix bug when displaying errors when generating textual program in standalone mode

Fix bug when compiling pou including user-defined blocks with unconnected input

Fix Segmentation Fault occurring when trying to open a new editor tab

Fix wire disappearing when wire tip and connector are not exactly at the same position fixed.

Adding '0' and '1' as possible value to force boolean variables

Adding support for saving frame size while closing and restore it at next launch

Fix dialogs positions to stay on the same screen than parent frame

Fix bounding box of Variable Block when variable name displaying size is bigger than block size

Fix bug with Function Blocks input and output position on Windows

Fix bug when buffering modifications on plain text languages

Modifying data stored in UndoBuffer to get a quicker Undo/Redo

Move position of debug value to avoid wire to cross text

Fix bug in block with execution control generation fixed

Fixed typo in PLCGenerator.py

Bug when using arithmetic functions (ADD, SUB, MUL, DIV) for TIME datatypes fixed.

Adding support for debugging and forcing DATE, DT and TOD in Beremiz interface

Dhu... Merged with myself...

Added drag'n'drop of functions and function blocks

Time funcs are now in Time categoryw