import from branch_2 commit 82057423c0f4aab59b1f9feede20dcac945b65b9 of my personal repository with some unused file removed to speedup git push.
fix gaussian blur, make it almost identical to vsfilter 2.39, the problem is mainly due to rounding error introduced in function generate_table.
add 2 test ass files and update test/issue.txt
make a simple MRU cache using boost::multi_index
Bug fix: fix potential false cache hit when transformation(scaling/rotation) is needed.
Add necessity check before transformation(scaling/rotation), skip unnecessary transformation.
Merge branch 'master' into mru

Conflicts:
	src/filters/transform/vsfilter/VSFilter_vs2010.suo
	src/filters/transform/vsfilter/vsfilter_2010/vsfilter_2010.vcxproj
	src/subtitles/RTS.cpp
	src/subtitles/Rasterizer.h
	src/subtitles/subtitles_vs2010.vcxproj.filters
fix \k effect family not working bug due to wrong criterion on whether the subtitle line has animated effect.
add a test file
And know issues.
fix crash cause by small blur strength(see test/issue.txt and test/5.ass).
fix incorrect result (see test/issue.txt and 6.ass) due to cache and default copy constructor of cword.
Add cache Manager make max cache item number configable
Add cache options to UI
Merge branch 'bug_fix' into mru

Conflicts:
	src/filters/transform/vsfilter/VSFilter_vs2010.suo
Add known issue. \be effect not working right.
update test/7.ass for \be not working right issue.
fix issue 5 (see test/issue.txt), make box blur effect identical to official VSFilter 2.39.
Add known issue, see test/issue.txt.
Simplified test/8.ass to just producing a issue.
fix issue 6 (see test/issue.txt). It was introduced in Commit 1a53708c33b730e88569ec42e11d4e833bf121fd.