Add 'newl' (synonym for 'newc') and fix the docs

Speed up variable creation/retrieval by replacing 'List_T *Symbols_L'
by 'Tree_T *Symbols_T'.

Fix includes with absolute paths

sync laptop and acm machine

Fix whitespace in copyright headers

Add Layer on Extrude Point (phase 2 -- remove duplicates)

Added Layer option for Extrude Point

Make headers self-contained

Add add these, too.

Clean up VERSION_FLAGS and OS_FLAGS (use HAVE_FLTK instead of _FLTK,
remove _BLACKBOX, etc.)

bump version to 1.37.0: system calls on Windows are now correctly implemented using the CreateProcess Windows API

Updated copyright

box of e.g. a view when merged in a script

Simplify error messages in parser a bit and change msg from ERROR to WARNING for list of shapes (less annoying when doing generic transformations, e.g. of points). Noticed this thanks to Genot Jean-Sebastien <JSGenot@HerouxDevtek.com>

compilation directives (cf. __APPLE__), were to rename the type
ColorTable to GmshColorTable and the function Palette to Palette1,
in order to avoid conflicts with Apple's QuickDraw.
Note that HFS is case-insensitive, which requires to have a fltk lib
name otherwise than libfltk.a (in the Mac version, the GL part is separate
anyway, so I've been using libfltk_base.a and libfltk_gl.a).