* src/pic16/pcode.[ch]: introduced pic16_stackpnt_*,

* src/pic16/pcode.[ch]: introduced pic16_stackpnt_*,
pic16_framepnt_*, pic16_stack_*, pic1_frame_* pointer variables to
access stack and frame pointers. They are initially assigned to
point at pic16_pc_fsr1[lh] and pic16_pc_fsr2[lh] variables and other
accessing SFRs. Updated all occurences of modification of stack or
frame pointer in gen.c and pcode.c,
* src/pic16/ralloc.c (serialRegAssign): fixed two bugs with
assigning of a literal value to pointers,
* src/pic16/main.c (pic16_finiliseOptions): set pre-processor define
flag STACK_MODEL_SMALL or STACK_MODEL_LARGE according to the model
selected

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3633 4a8a32a2-be11-0410-ad9d-d568d2c75423