* mu4e-header-highlight-face: inherit region

This should make it more intuitive to see that actions are performed
on the region as well as the current line (which usually is not part
of the region).
improve doc-strings

The first sentence should summarize the variable's or function's
purpose and it should fit on the first line.  Change existing
doc-string by:

* Move first sentence onto first line even if that makes it _a bit_
  long.
* Move additional notes out of first sentence and add them later,
  possibly as complete sentences.
* If I am uncertain whether doing the above would alter the meaning,
  _don't_ do it.
* If fitting the initial sentence on the first line would require a
  complete rewrite of the doc-string _don't_ do so unless it is very
  easy to do.
* Remove indentation from second and later lines if it is there to
  align them with the first in the source code, instead of in
  `describe-*' output.
* Make "pullet point" lists a bit more consistent.

Obviously this does not fix all problems but it's a start.
mu4e~header-line-format: use same font as in buffer

Use face `bold' for the sorted column but leave the face unspecified
for other columns.  This is how tabulated-list does it to; it only
uses fixed-pitch for whitespace between columns.

The problem with using fixed-pitch is that uses "Monospace" which
might be a different monospace font than what is used for `default'.
These fonts might have a different width causing columns in the header
and the buffer not to be aligned.

Inheriting `fixed-pitch' from `default' instead of specifying the font
does not work as that causes the `fixed-pitch'ed parts of the
header-line not to be raised like the rest anymore.  One (that is
every user) could also manually copy the font family from `default'.

Simply not specifying the font fixes all that.
mu4e: set symbol prop definition-name in defun macros

This allows `find-function' to find the definition.  While the
definition doesn't contain much useful information jumping there
instead of the beginning of the file is still better because the macro
used to define them is defined right above.

Also remove the comments about wanting to define the commands in a
loop.  One shouldn't do that; it would again make it impossible to
find the definition.
Merge pull request #89 from tarsius/fix-doc-strings

* improve docstring layout: 
 
    - Move first sentence onto first line even if that makes it a bit long.
    - Move additional notes out of first sentence and add them later, possibly as complete sentences.
    - If I am uncertain whether doing the above would alter the meaning, don't do it.
    - If fitting the initial sentence on the first line would require a complete rewrite of the doc-string don't do so unless it is very easy to do.
    - Remove indentation from second and later lines if it is there to align them with the first in the source code, instead of in `describe-*' output.
    - Make "bullet point" lists a bit more consistent.

  
Merge pull request #88 from tarsius/faces

* mu4e: make mu4e-header-highlight-face inherit region
Merge pull request #92 from tarsius/header-line

* mu4e: mu4e~header-line-format: use same font as in buffer
Merge pull request #94 from tarsius/definition-name

* mu4e: set symbol prop definition-name in defun macros