Fix for Keychain plugin

- Fix typo in `removeForKey` method
- Use one instance of cordova `Keychain` plugin
- Remove unnecessary function wrappers for promise callbacks
add httpd plugin to embed nano web server into cordova app
added plugin videoCapturePlus
include videoCapturePlus in modules
Merge pull request #457 from jonlil/master

Added videoCapturePlus plugin that allows for different recording qualities
Merge pull request #448 from khashayar/fix/keychain

fix(plugin:keychain): typo in removeForKey, one instance of cordova Keychain plugin
Merge pull request #453 from floatinghotpot/add_httpd_plugin

add httpd plugin to embed nano web server into cordova app
Adds support for PDF417 barcode scanner

https://github.com/PDF417/pdf417-phonegaptop