Install App Dependencies

- Spawns an npm install command from the App root
- Has some special OS checks for windows command spawning
Merge pull request #2099 from jgable/appDependencies

Install App Dependencies
Add link to README.md file about using ghost as 
a npm module

fixes #2008
Updated package.json to conform to npm standards

fixes #1053

- fleshed out script object 
- added test and install package.json
- updated contributing guide 
- updates travis.yml to leverage new npm start
Fix for broken filters where `this` context was lost.

fixes #2157
- Change tests to only check for existance
- Properly bind helpers/filters to their instance
Merge pull request #2165 from halfdan/2157-fix-filters

Fix for broken filters where this context was lost.
Rename unregisterFilter to deregisterFilter

fixes #2167
- Rename functions
- Adjust tests
Merge pull request #2168 from halfdan/deregister

Rename unregisterFilter to deregisterFilter
Merge pull request #2160 from hswolff/package-json-updates

Updated package.json to conform to npm standards
Merge pull request #2161 from hswolff/npm-module-doc

Add link to README.md file about using ghost as a npm module
Adds support for additional permalink structures

fixes #2057

- uses express’ Route object to create RegExp’s
 that we use to check the incoming path
- refactored structure of fronted controller single
 tests to be easier to read
- amend regex to incorporate new allowed permalink
 structure
Merge pull request #2116 from hswolff/permalink-upgrade

Adds support for additional permalink structures
Ensure filters get default priority if priority is null

- null priority should be set to the default
- second part to https://github.com/TryGhost/Ghost-App/commit/86619cb087774a3e7cae39b13527191e62fdf5a4
Cleanup dependency order in package.json

- because OCD