[dfmc-conditions] with-simple-abort-retry-restart allows non-constant expressions.
Nicer error message for dswank when no project set

When using DIME and you try to compile the file without setting the
project, you got a method missing error on #f, #f being the missing
project receiving a message.

Added a nil check on *project* in dswank to throw an error with a more
obvious message, which surfaces back on the Emacs side as:

Evaluation aborted on Error: A project has not been set
Merge pull request #756 from erikcharlebois/master

Nicer error message for dswank when no project set
Merge pull request #755 from waywardmonkeys/dfmc-conditions-expressions

[dfmc-conditions] with-simple-abort-retry-restart allows non-constant expressions
[dfmc-common] Restore compilation pass setup code.
[dfmc-optimization] Re-enable set up of compilation passes.
[dfmc-flow-graph] Support passing symbols to ensure-invariants.
[dfmc-management] Enable running passes.

When OPEN_DYLAN_RUN_PASSES is defined in the environment, the
optimizer will run via optimization passes.
Hacks.