[REF](protovis Dom) Some code optimizations and made the childNodes property, initially, an array of the prototype, being created locally on firt child addition.
[REF](Data childNodes) Removed the duplicate _children property of the Data class. Now always using the childNodes property provided by the pv.Dom class mixin. Also all direct accesses to te data._childrenByKey property were replaced by a call to data.child(key).
(cherry picked from the AdvOpt branch)
[WIP](protovis pv.Dom.Node) Added #_childAdded and #_childRemoved handlers to better serve derived classes (Data, Dimension, Scene...)
[FIX](protovis JsDocs GoogleCompiler) Made google compiler happier with the used type annotations. (cherry-picked from AdvOpt)
[FEAT](CartesianAxis FixedMin/Max options) The FixedMin and FixedMax options now support reading values in the corresponding dimension's source format - the one used to read data from the data source.
[FEAT](timeSeries FixedMin/Max options) Cartesian axes of Date type now also support the FixedMin and FixedMax options (until now only implemented for numeric axes).
[CHG](timeSeries) Improved code of time series scale calculation in that it now better handles degenerate conditions like 0-length or negative length intervals.
[FEAT](timeSeries) The default converter created for date dimensions now accepts numbers (date in milliseconds), Date objects, as well as the already supported strings in the default/specified date format.
   This affects data source reading, but, as well, of "FixedMin" and "FixedMax" cart. axis options and of base values specified in the pvc.CartesianChart#markEvent method.
[DOC](FixedMin/Max options) Updated documentation of cartesian axis' FixedMin and FixedMax options, to reflect the supported data types and formats.
[DOC][FIX] Fixed some invalid links.