tryout design of filter support
simple counter creation
handle travis complaint
travis weirdness
on 500 write error string
travis tryout
travis tryout (2)
travis tryout(3)
restore old travis file
travis -> drone
implemented webservice and route level filter chains

see restful-filters.go for an example
fix Filters() in WebService
add global filters
docs about filters and errors
add tests for filters
add basic authentication example filter
add links to docs
cache regex compilation result in PathExpression