Merge pull request #5 from ralphbean/master

Grammar fixes
more help for installation - fixes #6
added a way to call a function to provide data - fixes #3
prep for 0.3
Avoid crash when server header is None

On some tests, possibly triggered by #7, boom would crash in `print_server_info` because it used string concatenation, which fails when the value is `None`. This commit avoids the crash but doesn't fix the underlying missing header value.

```
Traceback (most recent call last):
  File "/Users/cadams/Library/Python/2.7/bin/boom", line 8, in <module>
    load_entry_point('boom==0.3', 'console_scripts', 'boom')()
  File "/Users/cadams/Library/Python/2.7/lib/python/site-packages/boom/_boom.py", line 207, in main
    args.method, args.data, args.content_type, args.auth)
  File "/Users/cadams/Library/Python/2.7/lib/python/site-packages/boom/_boom.py", line 136, in load
    print_server_info(url, method)
  File "/Users/cadams/Library/Python/2.7/lib/python/site-packages/boom/_boom.py", line 77, in print_server_info
    print 'Server Software: ' + res.headers['server']
TypeError: cannot concatenate 'str' and 'NoneType' objects
```
Merge pull request #8 from acdha/patch-1

Avoid crash when Server header is None
Fix HTTP Basic Authentication
Merge pull request #9 from vstoykov/master

--auth option Does not work
Merge branch 'master' of github.com:tarekziade/boom
started to add some tests
typo
added --header support + Home support
header syntax
added header to docs
Allow custom headers with multiple requests

Previous the --header option was a mutually exclusive option with --requests /
--duration, which appears to be an oversight. Custom headers work well in my
testing
Merge pull request #10 from acdha/allow-custom-headers-with-requests

Allow custom headers with multiple requests
Fix typo in automatic Host header support

This was previously setting the header as "Home" when the resolved
IP didn't match the original request.
Include request headers in displayed server info
Merge pull request #11 from acdha/verbose-custom-headers

Display request headers in server info
removed the group