LanguageToolPython 2.6.1

LanguageToolPython 2.6.1 upgrades our LanguageTool version to 5.4, which gives us the main benefit of all of the additional error detection rules added to LanguageTool 5.4 across the many languages LanguageTool supports.

Behind the scenes, I cleaned up the code a bit, and changed our web requests to use the Python requests library across the board. There had still been some legacy code that made calls to the raw urlopen() python binding, which caused various issues (such as #42) and was generally persnickety. Hope this works better!