docs: add reference to installation and building in README

fixes machinekit/machinekit#362
Added arm335x eQEP enconder support
Added documentation for hal_arm335xQEP driver
Merge pull request #394 from russellgower/bbb_eqep

Added arm335x eQEP enconder support
Merge pull request #395 from mhaberler/master

gladevcp: example configs were broken due to API change
Merge pull request #393 from luminize/fix-readme-ref

docs: add reference to installation and building in README
build: fix webtalk clean target

cant have multiple identically named targets - newer overrides older.