calc 2.15.0.5 release

The following are the changes in this release:

 make clobber now removes the legacy files: have_fpos.h, help/man,
 and help/usage.  The latter 2 are now managed as help aliases
 in help.c.

 make install now removes the legacy files: ${HELPDIR}/man
 and ${HELPDIR}/usage.

 Fixed a problem where, when calc was linked with and uses GNU
 readline then for any multi-line copy-and-paste, only the first
 line is executed.  Thanks to GitHub user @malfisya for reporting
 this problem, and thanks to GitHub user @gromit1811 for doing
 the research needed to overcome deficiencies in the GNU readline
 documentation, and for supplying the work-a-round to allow
 multi-line copy-and-paste to work as expected!