gitignore: add cabal sandbox dir/file
Add command findsymbol
Error message for 'findsymbol', if no modules could be found
Handle GHC exceptions
findsymbol with sourcefile
Allow multiple source files for 'findsymbol'
Don't output any GHC warings/errors for the 'findsymbol' command
Return each module only once
Load each file/target separately for the 'findsymbol' command

To be able to continue loading of files and reading their module
graph if an error occured during the loading of a file, because
if all files are loaded at once, then GHC stops the loading
if an error occured.
Merge branch 'master' of https://github.com/dan-t/hdevtools