mereged master and my copy
Merge pull request #10 from mkotov/eqs

mereged master and my copy
added comments to solutions of inequalities
added comment 'I don't know how to solve'
Merge pull request #11 from mkotov/eqs

added comments to solutions of inequalities
added function compute(); added procesing = and ==, dx
Merge pull request #12 from mkotov/eqs

added function compute(); added procesing = and ==, dx
implicit operations
improved compute()