Suppress warning about non-existing path given to -I with --quiet.
value flow: loosen up bailouts in valueFlowSubFunction
astyle formatting
GUI: add the cfg files in the resources. use these as fallback when normal loading fails.
value flow: fixed fp for rhs in && and || expressions
value flow: improved analysis of expressions below ?, && and || operators
value flow: changed astparent lookup
value flow: bailout in valueFlowBeforeCondition if variable can be assigned by subfunction
value flow: refactoring. broke out function for skipping value simplifications in expressions.
Fixed #5334 (False positive: same expression on both sides of '||')
ast: fixed syntax tree for statement enclosed in parentheses ';(expr);'
value flow: bailout when variable is used in assignment to itself
value flow: fixed fp when while condition contains variable that is changed in loop body
value flow: fixed fp for nested assignments
value flow: don't perform value flow analysis in sizeof/typeof expressions
value flow: fixed fp in switch
travis: rewrite config file.

Uses CXXFLAGS -O2 instead of default flags to speed up self checking.

Testing is done with the following settings:

1) gcc    CXXFLAGS=-O2
2) gcc    CXXFLAGS=-O2  SRCDIR=build VERIFY=1
3) gcc    CXXFLAGS=-O2  MAKEFLAGS="HAVE_RULES=yes"
4) gcc    CXXFLAGS=-O2  SRCDIR=build VERIFY=1  MAKEFLAGS="HAVE_RULES=yes"
5) clang  CXXFLAGS=-O2
6) clang  CXXFLAGS=-O2  SRCDIR=build VERIFY=1
7) clang  CXXFLAGS=-O2  MAKEFLAGS="HAVE_RULES=yes"
8) clang  CXXFLAGS=-O2  SRCDIR=build VERIFY=1  MAKEFLAGS="HAVE_RULES=yes"

Changes made to before_install:
installe libpcre3

Changes made to script:
* make and make test are now called seperately
* cppcheck also checks "build" folder (created by SRCDIR=build) if existing.
* gui is built twice, one time with HAVE_RULES=yes as qmake argument and one time without it.
* a script has been added and run which returns false if cppcheck --showtime=top5 does not return 7 lines indicating that something is broken
travis: use suppression list to suppress warnings.
travis: also check "test" directory while ignoring test.cxx
travis: check cfg files with xmllint.