Fix find_file function
Fix #247 - Check whether expected project paths exist

Until now, we were assuming that the 'web' and 'bin' path always
existed. Now we check whether they actually exist.
Add assertion
Return early if path does not exist
Merge pull request #251 from my-personal-forks/fix-missing-paths

Fix #247 - Check whether expected project paths exist
Merge pull request #250 from my-personal-forks/fix-tests

Fix find_file function
Prepare release
Merge pull request #252 from my-personal-forks/prepare-release

Prepare release
Rename dart_project --> pub_package
Rename DartProject --> PubPackage
Merge pull request #254 from my-personal-forks/rename-dart_project

Rename dart_project --> pub_package
Detect and run files under 'example'

- Run as script if file is .dart file and contains 'dart:io' import
  or if file is .dart file and does not contain 'dart:html'.
- Else, serve 'example' dir via pub.
Merge pull request #255 from my-personal-forks/run-examples

Detect and run files under 'example'
Fix #11 - Improve syntax def when using 'library' keyword
Merge pull request #256 from my-personal-forks/fix-11-library-keyword

Fix #11 - Improve syntax def when using 'library' keyword