minor changes to frontend
fix description of how to use sbt-idea

(it's an external plugin now no longer referenced
from within the sbt scripts)
cosmetic improvements in frontend
explaining formula
merging ckaestne/master
fix compile errors; add todos for incompatible code (does not compile)
cleanup imports
update ifdeftoif description
add missing import; organize imports
remove unnecessary constant; update comment
renaming refactoring
fix typo
code layout
refactor bddfexp to cexp
code simplification; intellij warnings
update comment
code layout
update ifdeftoif description
refactoring and code layout
code layout