Add Travis CI config
Use RStudio binary for pandoc, rather than installing through cabal
Add Travis build shield
Fix directory-changing logic
Move CMTK installation to before_install in Travis config
Add display of cmtk.bindir() output
fix typo syntax error
binary install some more packages

* igraph is big
and filehash
no need to install devtools
Print system path and which cmtk
remove debugging prints now travis OK

* the problem was that nat::cmtk.bindir() failed when the only part of cmtk visible was:

  /usr/bin/cmtk

There is now special handling for the cmtk wrapper script.
binary installs of some more packages
fix name of RcppEigen package
Merge branch 'travis'

* travis:
  fix name of RcppEigen package
  binary installs of some more packages
  remove debugging prints now travis OK
  Print system path and which cmtk
  no need to install devtools
  and filehash
  binary install some more packages
  fix typo syntax error
  Add display of cmtk.bindir() output
  Move CMTK installation to before_install in Travis config
  Fix directory-changing logic
  Add Travis build shield
  Use RStudio binary for pandoc, rather than installing through cabal
  Add Travis CI config