quill: Avoid signal-handler in URL input loops

BASH changed the context of signal handlers, and now they can't break
out of loops in the triggering context.

It's use has always been a hack, so signal the user wish to ignore the
checks via an empty input string instead.

libcopy: Update the index instead of re-indexing

This makes initial copies much faster.

quill: Simplify parsing of Github URLs

Extract the name using a fixed index; counting from the end can vary the
relative index in case of full refs.

Fixes: 4668bcd70ba8 ("quill: Fix parsing of Github URLs")

libdetails: Unify and simplify URL sanitization

install.sh: Simplify setting INSTALL_ROOT variable

libcore, libdetails: Fix naming of Github tarballs

libdetails: Fix parsing non-prefixed version

quill: Fix parsing of Github URLs

libperlcpan: Prefix spell name with "perl-"

libdetails: Improve parsing of SPELL_SRC_FILE

Get rid of the SPELL_SANITIZED_FILE_NAME variable, and parse Github-style
URLs correctly.

libupdate: Colorize multiversion_check suggestions

libupdate: Improve multiversion_check suggestions

More comprehensive collection with de-duplication in a single command
invocation. Also, suppresses spell description.

libhackagedb: Ignore more packages included in GHC

libhackagedb: Fix parsing of description field

Trims white-space at the beginning of lines, fixes detection of the field
ending, and corrects handling of empty lines.

libhackagedb: Fix handling of build-depends field

libhackagedb: Handle cabal fields case-insensitively

libhackagedb: Prefix spell name with "haskell-"

libhackagedb: Fix parsing of build dependencies

libhackagedb: Build source URL from information in the cabal file

libhackagedb: Implement simpler description parsing (in AWK)