add DeptaIBLExtractor and DeptaExtractor to extract data from aligned data found by Depta
more fix and improvement:

* fix DeptaExtractor to make it extract item not contiguous in page
* always use unicode inside for region's text and encode as utf8 when output
* improve the identify_region to select the region has max average score
add DeptaTemplateMaker to annotate next match fields if need
Merge pull request #8 from tpeng/patch-1

add DeptaIBLExtractor and DeptaExtractor to extract data from unseen pages