Allow empty values

It is a legitimate use case to set empty values; to override a
default when an empty value is acceptable for instance. This patch
changes the regex in three ways: it 1) removes the requirement for
a non-whitespace terminator on a setting value, 2) makes the value
match non-greedy so that the \s*$ at the end can catch the newline
and 3) changes the \s*=\s* to [ \t]*=[ \t]* because we don't want
that to capture *any* whitespace (like a newline).
Tweak the Gemfile to be better for development, add a Rakefile.
Merge pull request #1 from apenney/52-otherwiseguy

PR #52
support for whitespaces in settings names (need for smb.conf)

smb.conf contains settings names with white spaces, for example

[globel]
server role = active directory domain controller
check password script = Disable
Merge pull request #2 from apenney/51-ivanov-aleksey

support for whitespaces in settings names (need for smb.conf)
Add a spec test to make sure spaces are handled properly for #51.
Merge pull request #3 from apenney/51-specs

Add a spec test to make sure spaces are handled properly for #51.