Merge pull request #140 from ktakagaki/filter1

Filter1
Update documentation link in the readme.
Added basic PCA implementation and unit tests.
Made matrix equality checks more lenient in PCA tests.
Merge pull request #152 from jasonbaldridge/master

Added basic PCA implementation and unit tests.
fix to 	#151
Merge remote-tracking branch 'scalanlp/master'
formatting, and use new-style breeze variance
a new method "convert" that casts collections from one type to another.
log determinant
cond(A) for computing condition number of a matrix. Fixes #129
documentation for logdet
End slicing cleanup
Merge branch 'master' of https://github.com/scalanlp/breeze into filter1

Conflicts:
	src/test/scala/breeze/linalg/LinearAlgebraTest.scala