Add Boa component

Boa is a single-tasking HTTP server. That means that unlike traditional
web servers, it does not fork for each incoming connection, nor does it
fork many copies of itself to handle multiple connections. It internally
multiplexes all of the ongoing HTTP connections, and forks only for CGI
programs (which must be separate processes). Preliminary tests show boa
is capable of handling several hundred hits per second on a 100 MHz
Pentium.

Description from : <http://packages.debian.org/squeeze/boa>
Building method inspired by :
<http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/www-servers/boa/boa-0.94.14_rc21.ebuild?view=markup>

component/boa/buildout.cfg

+[buildout]
+
+parts = boa
+
+[boa-patch-ENOSYS]
+recipe = hexagonit.recipe.download
+url = http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/www-servers/boa/files/boa-0.94.14_rc21-ENOSYS.patch?revision=1.1
+filename = boa-0.94.14_rc21-ENOSYS.patch
+md5sum = 7206b342195961501ed1eae38486e5db
+download-only = true
+
+
+[boa]
+recipe = slapos.recipe.build
+url = http://www.boa.org/boa-0.94.14rc21.tar.gz
+md5sum = e24b570bd767a124fcfb40a34d148ba9
+patches =
+    ${boa-patch-ENOSYS:location}/${boa-patch-ENOSYS:filename}
+slapos_promise =
+    directory:bin/
+    file:bin/boa
+    file:bin/boa_indexer
+script = 
+    import shutil
+    import os
+    url = self.download(self.options['url'], self.options['md5sum'])
+    extract_dir = self.extract(url)
+    workdir = guessworkdir(extract_dir)
+    self.applyPatchList(self.options.get('patches'), '-p1', cwd=workdir)
+    call(['./configure'], cwd=workdir)
+    call(['make'], cwd=workdir)
+    # Installation of boa. Manually, no make install
+    os.makedirs('%(location)s/bin/')
+    shutil.copyfile(workdir + '/src/boa', '%(location)s/bin/boa')
+    os.chmod('%(location)s/bin/boa', 0755)
+    shutil.copyfile(workdir + '/src/boa_indexer', '%(location)s/bin/boa_indexer')
+    os.chmod('%(location)s/bin/boa_indexer', 0755)