Escape a literal # in the iemguis so that it can be used inside labels.

This fixes #427.

We do this by tacking on a tilde if # is followed by a digit, to prevent it
from being mistaken for a $ substitution (which happens because $ becomes # in
FUDI, which is required behavior by non-iem gui objects and thus we don't want
to break this). The tilde gets removed automatically when the label is sent to
the gui.

All this is implemented using the existing symbol mungers in the
iemgui_dollar2raute and iemgui_raute2dollar functions in g_all_guis.c and
iemgui_escape and iemgui_unescape in dialog_iemgui.html.
10 jobs for fudi-dollar-mapping in 310 minutes and 32 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test
passed #8621
debian stable amd64
debian_stable_amd64_deb

00:29:54

passed #8629
debian arm stable
debian_stable_arm_deb

00:47:54

passed #8620
debian stable i386
debian_stable_i386_deb

00:36:07

passed #8622
debian stretch amd64
debian_stretch_amd64_deb

00:31:11

passed #8627
osx v10.8 dmg
osx_10.8_amd64_dmg

00:19:51

passed #8626
osx v10.11 dmg
osx_amd64_dmg

00:21:23

passed #8624
ubuntu v14.04 amd64
ubuntu_14.04_amd64_deb

00:30:21

passed #8623
ubuntu v14.04 i386
ubuntu_14.04_i386_deb

00:33:47

passed #8625
ubuntu v16.04 amd64
ubuntu_16.04_amd64_deb

00:35:37

passed #8628
windows i386
windows_i386_installer

01:12:15