Cached files so they are only loaded once

`files` is an expensive method and is called a number of times. Added caching of the files and reload them in certain conditions
Merge pull request #109 from lukesmith/perf-improvement-options-glob

Cached files so they are only loaded once
Edited Readme, fixed unended ruby code block
Merge pull request #110 from Ortuna/readme-fix

Edited Readme, fixed unended ruby code block
Absolute path serving added
Dyn local file with absolute path detection added
Consolidate & simplify local_file_for & dyn_local_file_for
Merge branch 'absolute-from-path'
Fix indentation & spacing
Remove unnecessary return value
Replace test! method with `rvm all do rake test` cmd
Rewrite build! method as module
Add notes about upcoming version
Update HISTORY.md syntax
Rename HISTORY.md -> CHANGELOG.md
Release v0.2.4
Remove trailing spaces
Update rubygems link [ci-skip]
Update gemspec licence & authors [ci skip]
Fix gemspec typo [ci skip]