adding hook_mapstraction_rows_alter allowing other modules to alter the markers before rendering a map

#808134 by esteewhy: Implement polyline rendering, row plugin, libraries.module support and other improvements
Some other code formatting and minor style changes

* complete refactoring of how maps are rendered to allow for more generalized API usage outside of views
* Add default map type setting

complete rewrite of how view results are converted into the array which is sent on to the client for map rendering.
* respect any theming, overrides, and rewrites applied to the fields used in the map
* code clean up
* cruft removal

This is the initial commit of the 6.x-2.x branch of the module, now with a new maintainer and hopefully some fresh life. Key changes so far include the following.
* Use v2 of the mapstraction library
* Add support for marker attributes, which you can map to a field in the views style
* Add a separate template file and cooresponding preprocess function to render a map