Operator brackets ([]) implemented in CL backend via fetch-property.

It allows the use expressions like "$myvar['myproperty']" instead of
"$myvar.myproperty".
Merge branch 'master' of github.com:archimag/cl-closure-template
Revert "fix indentation in closure-template-html-mode"

This reverts commit bfeda732b3293d0e4c76dafaa141c06adf8ece92.
Improved closure-template-html-mode