code/style improvements

Removed redundant command line arguments from server.py

Beginning to standardize on single-quoted strings unless necessary to
use double-quoted strings (easier to read and understand the code).

Beginning to standardize on tab-based indenting rather than space-based
indenting. Each tab is 3 spaces wide so that the tabs are not
ridiculously large.

Improved configurability, made documentation more easily
human-readable, minor variable name changes.

Rather than change the working directory from within server.py, pass
the argument into the TFTP or HTTP server (starting with TFTP, will
improve HTTP in later commit) so that the classes are more easily
callable by other modules.
updated README.md

updated README.md to reflect argument help from changes in previous
commit
updates to httpd.py

updated httpd to style with 3 space-wide tabs rather than spaces for
indenting

fixed the same default IP bug from TFTP server

changed default netbootDir parameter to current directory so that if no
directory is passed then the directory it looks for files is the same
as the one it’s in (updated this on tftpd.py also)
updated server.py

removed specifying netbootDir parameter as when calling multiple
daemons it’s best to chdir once in the main server.py rather than pass
it (causes confusion on the OS’s part)
modified dhcpd.py

updated dhcpd.py to meet style guidelines outlines in previous commit

fixed minor errors and hard-coded bugs
Merge pull request #13 from mmattioli/master

Code Improvements, Style Guidelines, Better Documentation, Minor Bug Fixes