Make smotitah dirs customizable & :type them.
Define a `smotitah` group for Customize

Thus resolving some compilation warnings:

    smotitah.el:270:1:Warning: defcustom for `sm-base-directory' fails
    to specify containing group
    smotitah.el:275:1:Warning: defcustom for `sm--profiles-dir' fails to
    specify containing group
    smotitah.el:279:1:Warning: defcustom for `sm--modules-dir' fails to
    specify containing group
    smotitah.el:283:1:Warning: defcustom for `sm--packages-dir' fails to
    specify containing group
    smotitah.el:290:1:Warning: defcustom for `sm--template-dir' fails to
    specify containing group
Add missing docstring to `sm--template-dir`.
Clean up whitespace. (trivial)
Fix `sm-package` error behavior

Because the variable `name` was still part of the quoted
expression, the error message in the assertion actually never got
displayed! Instead, a cryptic error appeared in the minibuffer:
"Symbol's value as variable is void: name".
Merge pull request #6 from MerelyAPseudonym/master

Let me put my smotitah files in a single subdir