fix search order for included files

first search the global include directories, unless the file name starts
with ./, then search relative to the current file.
add AST pretty printer
reject numeric floating point literals that are actually inf
while printing the ast, make sure that floats round-trip
remove superfluous newline from printed ast
make write statement target a real EndpointExpr
basic semantic analysis for the the new language
move type operations to their own header
make diagnostic handling a bit nicer

might be useful later when warning start to appear
properly check devices and endpoints in class instances