Simplyfied one interface and renamed some functions/variables.

Renamed former layer-* and annotate-* functions/variables to make
it clearer what they are supposed to to.  Simplyfied former
annotate-* interface.
* lisp/pdf-render.el:Renamed Functions and Variables. Simplified
hotspot interface.
* lisp/pdf-misc.el:Rename and use new interface.
* lisp/pdf-links.el:Dito.
* lisp/pdf-annot.el:Dito.
Ignore TAGS files.
Suppress warnings in synctex.

* src/Makefile.am (AM_CFLAGS):Separate synctex compilation and add -w flag.
* configure.ac:Configure ar program.
* .gitignore:Ignore *.a .
Fixed warning.

* lisp/tablist.el (tablist-edit-column-mark-field): Avoid compiler warning.
Corrected hotspot order.

* lisp/pdf-render.el:Use correct order for hotspots. Added
function `pdf-render-sorted-render-functions'.
Added text pointer.

* lisp/pdf-misc.el: Added text pointer over text regions.