Fix variable mew-image-display-resize ignored

The variable `mew-image-display-resize` was ignored and did not performed.
Merge pull request #54 from trueroad/fix-resize-flag

Fix variable mew-image-display-resize ignored
Add image resizing always flag

variable `mew-image-display-resize-always`
Change the image resizing command line option

pamscale option -xysize is obsoleted by -xyfit.
Merge pull request #55 from trueroad/image-resize-always

Add image resizing always flag
Fix indent
Add guard conditions
Move fboundp statement
Merge pull request #57 from yuutayamada/fix-self-insert-command

Fix self insert command #56
Update mew-regex-ignore-scan-body-list for a line beginning with "["
Merge pull request #58 from tats/bug/scan-body

Update mew-regex-ignore-scan-body-list for a line beginning with "["