4.5.2: fix screen size change when popped down

• Popup problem fixed where a screen size change would move the
  xlbiff widget as needed but then realize it even if it was
  supposed to be unrealized. Bug introduced in version 4.5.
• Doc: "Customizing" section moved from README.md to xlbiff.man

4.5.1: documentation updates

• Description in manual and README updated
• README.md is new name for README file, now in Markdown format

4.5: handle screen size changes with RANDR

• handle screen size changes with RANDR, so "xlbiff -bottom" stays at screen bottom

4.4: scanCommand can use temp profile

• scanCommand works even if user has not run mh-install

4.3: update X resources

• Removed "international: True" X resource.
  This was added in 4.2 and changed font resources incompatibly.
  Users for whom "international" was useful, or who had already updated
  their resources to handle it, can get the 4.2 behavior back by adding
  the following line to an X Resources file or -xrm argument:
  *international: true
• Update default font resource with the font's current name
• Changed default mail path directory to /var/mail from /usr/spool/mail
• Changed manual page name to xlbiff.1 from xlbiff.1x
• Install xlbiff.form to /usr/local/share/mh, not /usr/new/lib/mh
• Developers: Build proceess changed from Imake to Autotools.
• Developers: Assume modern C library and compiler.