Also add a Site::render_section method

Slighty smarter rebuild on page content change

Add global get_page tera fn

Sections

Useful if you're creating a section only to access it in the index but
do not want a section page for it

Pagination

Fix #53

Allow sorting pages by order and date

Closes #14, #43

Fix #51

Index page

Avoid issues with temp files from some editors

Add more sublime syntaxes

The packdumps contains the fixed Linker syntax too so it can be
used