Fix various verilog-mode.el issues.

Fix various verilog-mode.el issues.

* lisp/progmodes/verilog-mode.el (verilog-read-decls): Fix SystemVerilog
2012 import breaking AUTOINST.  Reported by Johannes Schaefer.
(verilog-auto-wire-type, verilog-insert-definition): Fix AUTOWIRE using
logic in top-level non-SystemVerilog module, bug1142.  Reported by Marcin K.
(verilog-define-abbrev-table) (verilog-mode-abbrev-table): Don't expand
abbrev inside comment/strings, bug1102. Reported by Slava Yuzhaninov.
(verilog-auto): Fix AUTORESET widths pulling from AUTOREGINPUT,
msg2143. Reported by Galen Seitz.
(verilog-modify-compile-command): Fix expansion of __FLAGS__ when
compile-command is globally set, bug1119.  Reported by Galen Seitz.