Add a DUB configuration to compile as a library without curl support.

Fix running executables that are not built in the CWD and create the target path if necessary.

Build to a temporary folder only if necessary. Fixes #82.

Remove dub.internal.std.process compatibility code as it doesn't support browse() and the compile status on older DMD versions isn't tracked anyway.

Move dub.utils to dub.internal.utils and update copyright dates.