add 'navbar-text' bootstrap element

separate 'divider' bootstrap element
correct some other specs
correct Readme
release v1.0.0
correct name_generator according to new simple-navigation
release v1.0.1
add ruby 2.1.1 to travis
add ruby 2.1.0 to travis
add coveralls gem
refactor rendering

correct and add badges to README
release v1.0.2
fix bug in stylesheet with 'divider-vertical'
remove '.rvmrc' file from repository