CB-5495, CB=5568 fix config.xml path for ios
Add release notes for the last few releases
CB-5701 Reference custom frameworks usinexecHelperrelative paths

Also changed where the frameworks are copied to. They now live within
the plugin's subdirectory (beside its source files) instead of at the
top of the project.
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