Added ASM lexer.
Lexer tweaks.
HTML and XML lexers maintain their states better.
Fixed bugs related to HTML lexer changes.
Fixed slowdown in processing long lines for folding; lexers/lexer.lua
Fixed slowdown with large HTML files; lexers/hypertext.lua
The tradeoff is that plain text like "2 + 2 = 4" highlights improperly.
Fixed 'preprocessor' style in themes.
Separated C/C++ lexer into ANSI C and C++ lexers.