White space & style fixes.
CB-5006: Add --searchpath option for local plugin search path
CB-5720 add resource-file to plugin.xml
CB-5720 Tests and formatting tweaks to <resource-file>
CB-4871 Switch to plist-with-patches to save ~10meg of test files in node_dependencies.
CB-4871 Remove unused dep "ncallbacks", move osenv to devDependencies
CB-4871 Add spec/ to .npmignore
Fix-up trailing comma in previous commit :(
Update xcode npm dependency version now that pull request is merged.
CB-5770 plugman prepare.js script content wrapping no longer allows ending parens/braces to be commented out from end of line comment
CB-5006 Change searchpath to use repeated flag instead of delimiter

The colon can't be used as delimiter for Windows paths like C:\...
Instead of using a delimiter, this change allows to repeat the
--searchpath flag for each additional directory to be searched.
The value for each path is resolved relative to the current dir.
Example:
--searchpath ../my_plugins --searhcpath /usr/lib/other_plugins

The dirs are searched in order. Search is not recursive and will only
look one level down. It will look for
my_plugins/plugin_x/plugin.xml
but not for
my_plugins/bunch_of_plugins/plugin_y/plugin.xml
CB-5006 Fix searchpath not being passed to dependent plugins.
CB-5802 Updated version and RELEASENOTES.md for release 0.18.0
Bump node-xcode dependency version
Update node-xcode dependency to 0.6.6
CB-5299 Cache pbxproj to avoid re-parsing it for each plugin.

Parsing pbxproj is very slow (~250ms on my machine). It is done for each plugin
that needs to add frameworks to the ios project. This change is a quick and
dirty fix to allow caching the parsed pbxproj object so that it can be reused for
multiple plugins during prepare.

Timings on a test project for cordova prepare ios:
before: 1.623s
after:  0.981s
CB-5804: added repo & issues to plugman publish
CB-5891 Fix engine check when path has spaces.
updated release notes
Setting version to 0.19.0