goblin: Go implementation of the 9base/Plan 9 command line tools.

This project is an idea presented at suckless.org/project_ideas.  Per their
project requirements the following tools will be covered in this project:

ascii - interpret ASCII characters
basename - strip file name affixes
bc - arbitrary-precision arithmetic language
cal - print calendar
cat - catenate files
cleanname - clean a path name
cmp - compare two files
date - date and time
dc - desk calculator
du - disk usage
dd - convert and copy a file
diff - differential file comparator
echo - print arguments
ed - text editor
factor - factor a number
fortune - sample lines from a file
fmt - simple text formatters
freq - print histogram of character frequencies
getflags - command-line parsing for shell scritps
grep - search a file for a pattern
hoc - interactive floating point language
join - relational database operator
look - find lines in a sorted list
ls - list contents of directory
mk - maintain (make) related files
mkdir - make a directory
mtime - print file modification time
pbd - working directory
primes - generate large primes
read - catenate files
sam - screen editor with structural regular expressions
sha1sum - sum and count blocks in a file
sed - stream editor
seq - print sequences of numbers
sleep - suspend execution for an interval
sort - sort and/or merge files
split - split a file into pieces
strings - extract printable strings
tail - deliver the last part of a file
tee - pipe fitting
test - set status according to condition
touch - set modification date of a file
tr - translate characters
troff - text formatting and typesetting
unicode - interpret Unicode characters
uniq - report repeated liens in a file
unutf