Initial port to SBCL.
Fix copy-stream so it understands buffered-stream in SBCL.
Better handling of standard streams.
ensure-buffered-stream
Clean up stream handling. Now both internal and external piping works for both LispWorks and SBCL.
Some small cleanups.
Better comments on the different combinations of element-type/external-format for SBCL, plus some further code cleanups.
Added code for error handling.
Merge branch 'sbcl-port' into sbcl-port-merge / current master branch.

Conflicts:
	README.md
	elprep-package.lisp
	elprep-utils.lisp
	elprep.asd
	filter-pipeline.lisp
	lisp-utils.lisp
	mark-duplicates.lisp
	sam-files.lisp
	sam-types.lisp
	split.lisp
	user-interface.lisp
Missing skip-header in merge code.
Small changes.
Portable pathnames in split and merge tools.
Added split and merge tools to package definition.
Removed superfluous print from python wrapper.
Merge branch 'sbcl-port-merge' of https://github.com/ExaScience/elprep into sbcl-port-merge
Calling open-sam instead of open-stream in merge UI.
Added proper error logging for SBCL.
Merge branch 'master' into sbcl-port-merge

Conflicts:
	buffer.lisp
	elprep-utils.lisp
	user-interface.lisp
Call buffer-parse-integer less often in the merge step.
Use copy-stream to copy remainders of files in the merge step.
Add a deterministic option to mark-duplicates.
Make some buffer functions reinitialize their targets by default, so client code becomes easier to read.