cleanup header dependencies; dpb should not need encoder.h

--HG--
extra : rebase_source : 00d38b16b01161e7d670cbca42ddbeba2f606403
search: store rd costs in first pass through intra modes

no behavior change, this is prep work for further refactors

--HG--
extra : rebase_source : a3c5daf8ca0b8df7d604c065086ea1fcb30b4b46
search: don't pass top-level encoder to initSearch()

removes three Encoder members that were only used to communicate data to
initSearch()
analysis: nit
dpb: does not need to include frameencoder.h
search: remove x prefixes from ME helper functions
analysis: minor comment and code cleanups, no behavior change
api: add analysis data structures and param options
api: introduce methods to allocate and free analysis buffers
store analysis information in buffers
cli: add cli options analysis-mode and analysis-file

analysis-mode: save|1 - Dump analysis buffers into file, load|2 - read analysis buffers from the file
analysis-file: Specify file name used for either dumping or reading analysis data