If brew create can't figure out the name, prompt for it

This was adapted from adamv@d5e78ee26535dec4b11c33d14832a9ee945a29fd

I decided prompting would was the most usable solution here, as the stem is
unlikely to be useful so the user would have to rename the file and change
the class name as well as type the command once and then again with --force.

Dissent welcome.

Fixes Homebrew/homebrew#15

Library/Homebrew/brew.h.rb

@@ -21,21 +21,16 @@
 #  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 #  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
-def make url
+def __make url, name
   require 'formula'
 
-  path=Pathname.new url
-
-  /(.*?)[-_.]?#{path.version}/.match path.basename
-  raise "Couldn't parse name from #{url}" if $1.nil? or $1.empty?
-
-  path=Formula.path $1
+  path = Formula.path name
   raise "#{path} already exists" if path.exist?
 
   template=<<-EOS
             require 'brewkit'
 
-            class #{Formula.class_s $1} <Formula
+            class #{Formula.class_s name} <Formula
               url '#{url}'
               homepage ''
               md5 ''
@@ -89,6 +84,27 @@ def make url
 end
 
 
+def make url
+  path = Pathname.new url
+
+  /(.*?)[-_.]?#{path.version}/.match path.basename
+
+  unless $1.to_s.empty?
+    name = $1
+  else
+    print "Formula name [#{path.stem}]: "
+    gots = $stdin.gets.chomp
+    if gots.empty?
+      name = path.stem
+    else
+      name = gots
+    end
+  end
+  
+  __make url, name
+end
+
+
 def info name
   require 'formula'