Merge pull request #62 from yuronew/master

fixes #60 and fixes #61
added credits for Yuriy and Ewald
removes duplicate test CompressedVectorTest.testSwap1()
Merge pull request #63 from ewaldgrusk/remove_duplicate_test

Removes duplicate test CompressedVectorTest.testSwap1()
Merge branch 'master' of github.com:vkostyukov/la4j