Add snippets for requirejs module definitions for coffee- and javascript

The snippet that generates a require block is called `reqjs` in order to
have no collision with the existing `req` snippet.
Avoid collision with print_r snippet
More adecuate naming
add pandoc snippet for UltiSnips
Update snippets.
pull request review
Remove useless placeholder
Add tex hyperlink snippets.
Merge pull request #429 from cirosantilli/tex-hyperlink

tex: Add hyperlink snippets.
Merge pull request #428 from heytitle/master

Perl: Adds dump and subtest snippets.
correct option
README improvements: md style, typos, fix links.
Rename node p to pipe.

Otherwise, conflicts with p for paragraph in html with default settings.
Merge pull request #431 from cirosantilli/readme

README improvements: md style, typos, fix links.
Add <th> in html
Merge pull request #433 from filipegiusti/add_th_to_html

html: Add th
Merge pull request #432 from cirosantilli/javascript-p

js: Rename node p to pipe.
Fixes and CSS support

- Removed regular expressions since they break YCM previews
- Extends the CSS snippets so you can use CSS snippets in Sass
Merge pull request #434 from feju/master

SCSS: Adds extends css and removes unnecessary regular expression triggers.
Merge pull request #421 from ethervoid/pr_snippet_collision

php: Avoid collision with print_r snippet