Minor appveyor config file tweaks.
Reorganize / add comments to appveyor.yml file.
Tweak PowerShell command for easier debugging.
Bumping version to 0.4.5-0.
Move grunt.log into separate grunt-legacy-log module.
Remove no-longer-relevant grunt.log unit tests.
When no new tasks found via .loadTasks method, warn. Closes gh-1059.

* More specifically: warn, instead of error.
Remove "CONTRIBUTING.md" from .npmignore. Closes gh-1093.
Temp fix to grunt.file.delete for gh-1134.

* The issue is with .sync in rimraf@2.2.7, but 2.2.6 still works.
* See isaacs/rimraf#40.
* Hopefully this fixes the build again!
Update rimraf to 2.2.8. Closes gh-1134.
Update grunt-legacy-util to 0.2.0. Closes gh-971, gh-1129.
Test realpath cwd in file.isPathCwd and file.doesPathContain. Closes gh-1112.
Added grunt.task.exists method to check if a task exists. Closes gh-1131.
Add grunt.config.merge method to deep merge config data. See gh-1039.
Adding CHANGELOG changes for 0.4.5. Closes gh-1138.
Fix invalid YAML in CHANGELOG
Bumping version to 0.4.5.
Add appveyor.yml to npmignore

Thanks @XhmikosR
Merge remote-tracking branch 'grunt/master'