add a cachebust module to generate href with cacheBust

employ a file lastModified strategy for static content cache.
cachebust will generate the href with a cacheBust.
And the value of the cacheBust is the last modified time of the
static content file.

cachebust.href
input: the static content url,  such as: css/dev.base.css
output: url with cacheBust
        such as: css/dev.base.css?cacheBust=1376668916.87

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Adam King <rak@linux.vnet.ibm.com>
cacheBust parameter for static content caching

All references to the static content are supplemented with a cacheBust
parameter to cause cache misses whenever the content has changed

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Adam King <rak@linux.vnet.ibm.com>
set expires for static content caching

As Adam King suggested:
We don't think cache expires is a value that we will want a typical
admin changing as they would the other values in kimchi.conf.
so put the explicit value to just one place in the python code,
and comment that its a year, and have the other code reference it.
If we ever want to change it, we just need to update that one value.

after set the expires, the cilent can receive a response-head as follow.
response-head:
	HTTP/1.1 200 OK
	Content-Length: 55946
	Accept-Ranges: bytes
	Expires: Sun, 17 Aug 2014 08:27:06 GMT
	Server: CherryPy/3.2.2
	Last-Modified: Sat, 17 Aug 2013 08:26:23 GMT

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Xin Ding <xinding@linux.vnet.ibm.com>
Signed-off-by: zhoumeina <zhoumein@linux.vnet.ibm.com>
A module to check the pam authenticate

This authenticate base on PyPAM.
It is used to verify userid/pwd on the host system.
PyPAM is a universal package, it can be available on most distribution.
It can be available on el4~el6, f14~f19
http://pkgs.fedoraproject.org/cgit/PyPAM.git/

It is the same interface with python-pam.
but python-pam is not be available on rhel by pam
usage:
    from auth import authenticate
    authenticate(username, passwd)

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Shu Ming <shuming@linux.vnet.ibm.com>