Fixes for 77a22a8.
Fixes for 77a22a8.

Notes:
* Use one example block for each facet of behavior. In this case,
  hexencoding a blank string is a boundary case. It needs its own
  spec.
* Try to use complete grammar whenever possible. The articles 'a',
  'an', 'the' are words, too.
* Use separate example blocks for types of values that cause TypeError
  exceptions. The nil value is different than a random Fixnum.

Besides making the specs more explicit by separating the facets of
behavior, it also makes the specs more useful. An error handling
the empty string would mask whether a non-empty string was encoded
correctly. Failure to deal with nil would mask whether Fixnums are
handled correctly. This sort of conflation in the specs makes them
more difficult to use.

xaviershay/rubyspec,ericmeyer/rubyspec,terceiro/rubyspec,alexch/rubyspec,no6v/rubyspec,marcandre/rubyspec,jvshahid/rubyspec,enricosada/rubyspec,qmx/rubyspec,chesterbr/rubyspec,sgarciac/spec,godfat/rubyspec,Aesthetikx/rubyspec,iainbeeston/rubyspec,alex/rubyspec,DavidEGrayson/rubyspec,jstepien/rubyspec,mbj/rubyspec,yous/rubyspec,qmx/rubyspec,jvshahid/rubyspec,yb66/rubyspec,kachick/rubyspec,saturnflyer/rubyspec,markburns/rubyspec,ruby/rubyspec,Zoxc/rubyspec,ruby/rubyspec,JuanitoFatas/rubyspec,wied03/rubyspec,mrkn/rubyspec,iliabylich/rubyspec,no6v/rubyspec,rkh/rubyspec,julik/rubyspec,ericmeyer/rubyspec,benlovell/rubyspec,yaauie/rubyspec,bjeanes/rubyspec,metadave/rubyspec,wied03/rubyspec,agrimm/rubyspec,freerange/rubyspec,amarshall/rubyspec,xaviershay/rubyspec,griff/rubyspec,bl4ckdu5t/rubyspec,chesterbr/rubyspec,lucaspinto/rubyspec,jabley/rubyspec,DawidJanczak/rubyspec,calavera/rubyspec,lucaspinto/rubyspec,alindeman/rubyspec,sgarciac/spec,nevir/rubyspec,roshats/rubyspec,markburns/rubyspec,timfel/rubyspec,yb66/rubyspec,yaauie/rubyspec,oggy/rubyspec,nobu/rubyspec,alindeman/rubyspec,julik/rubyspec,mrkn/rubyspec,sferik/rubyspec,Aesthetikx/rubyspec,kachick/rubyspec,rdp/rubyspec,DawidJanczak/rubyspec,shirosaki/rubyspec,rkh/rubyspec,teleological/rubyspec,jannishuebl/rubyspec,bjeanes/rubyspec,benburkert/rubyspec,benlovell/rubyspec,flavio/rubyspec,kidaa/rubyspec,agrimm/rubyspec,ruby/spec,tinco/rubyspec,bomatson/rubyspec,teleological/rubyspec,scooter-dangle/rubyspec,MagLev/rubyspec,rdp/rubyspec,ruby/spec,kidaa/rubyspec,timfel/rubyspec,benburkert/rubyspec,BanzaiMan/rubyspec,josedonizetti/rubyspec,oggy/rubyspec,jstepien/rubyspec,neomadara/rubyspec,BanzaiMan/rubyspec,atambo/rubyspec,alex/rubyspec,shirosaki/rubyspec,MagLev/rubyspec,flavio/rubyspec,eregon/rubyspec,sferik/rubyspec,tinco/rubyspec,atambo/rubyspec,kachick/rubyspec,wied03/rubyspec,terceiro/rubyspec,enricosada/rubyspec,scooter-dangle/rubyspec,Zoxc/rubyspec,bl4ckdu5t/rubyspec,amarshall/rubyspec,griff/rubyspec,mbj/rubyspec,ruby/spec,metadave/rubyspec,roshats/rubyspec,nobu/rubyspec,jabley/rubyspec,josedonizetti/rubyspec,calavera/rubyspec,nevir/rubyspec,askl56/rubyspec,iainbeeston/rubyspec,neomadara/rubyspec,marcandre/rubyspec,godfat/rubyspec,freerange/rubyspec,bomatson/rubyspec,JuanitoFatas/rubyspec,askl56/rubyspec,DavidEGrayson/rubyspec,iliabylich/rubyspec,sgarciac/spec,nobu/rubyspec,jannishuebl/rubyspec,eregon/rubyspec,eregon/rubyspec,yous/rubyspec,alexch/rubyspec,saturnflyer/rubyspec