Merge branch 'master' of https://github.com/snap-stanford/ringo
Move ringo-engine to this ringo repo

ringo-engine now moved to ringo.  We have to hard code
dependencies to /snap-core and /glib-core in Makefile.config
, with the assumption that this code is in directory ../snapr
Change Name PNEAGraph->PNEANet.  Also, get rid of binaries
Add Atomic Select

Includes comparison between two cols and
between one col and a const value
Changed implementation of Group and Unique
Moved some redundancy from SelectAtomic implementation
added is-substring atomic predicate
Fixed graph creation bug - values of SrcCol and DstCol don't have to be unique - added GraphPrep and modified BuildGraphTopology; Added methods to TTable for setting graph information; Fixed gcc compilation error in Predicate.h; Added new benchmark and added graph creation to original benchmark
Implemented Order
fixed self-join bug
Implemented IsNextK filter
make GraphPrep method private. called from ToGraph
make GraphPrep method private. called from ToGraph
Make mapping between float nodes to graph node ids a field in TTable - instead of generating mappings and paaing it as arguments to each method
fixed bug in TTable::GetNId; added public methods AddNodeAttr (src + dst)
Added method SetCommonAttrs to treat src and dst attribute pair as a single attribute
Code clean-up and many modifications - described in a separate file
changes documentation for commit f573249e22eec43733de0eb49223a6aa5925c640
Added option for Select methods to be called with only a predicate argument
changed old tests to match recent changes in TTable interface