Adding Travis CI to automatically check builds
Adding Travis CI to automatically check builds

Current missing are:
- some compilation options that leads to error. They are not corrected
  right now as some of them may by corrected by PR#55
- checkpatch is not downloaded / run because of
  - licenses?
  - CamelCase in GP API that may lead to false alarms

Signed-off-by: Pascal Brand <0b55292d2562685bad4ce52d64f802e8f1cd299e@st.com>

chshxi1989/optee_os,jamescfkung/optee_os,matt2048/optee_os,Microsoft/optee_os,Microsoft/optee_os,BreezeWu/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,BreezeWu/optee_os,BreezeWu/optee_os,jamescfkung/optee_os,cedric-chaumont-st-dev/optee_os,BreezeWu/optee_os,chshxi1989/optee_os,Microsoft/optee_os,cedric-chaumont-st-dev/optee_os,pascal-brand-st-dev/optee_os,Microsoft/optee_os,cedric-chaumont-st-dev/optee_os,matt2048/optee_os,jamescfkung/optee_os,BreezeWu/optee_os,chshxi1989/optee_os,matt2048/optee_os,matt2048/optee_os,pascal-brand-st-dev/optee_os,jamescfkung/optee_os,Microsoft/optee_os,chshxi1989/optee_os,chshxi1989/optee_os,cedric-chaumont-st-dev/optee_os,pascal-brand-st-dev/optee_os,jamescfkung/optee_os