2010-06-14
* version 1.0.1 to 1.1.1
* removed empty sections from .Rd files
* dag.init
- now adds version of dagR to the DAG
- now assigns class "dagRdag" 
- elaborated documentation regarding node numbering
* rm.node, add.arc, rm.arc
- now also remove searchType and searchRes
* dag.adjust
- if adjustment set not empty, now also removes searchType and searchRes
- elaborated documentation regarding node numbering
* is.acyclic
- new argument: maxSecs
* new function: viv
* new function: msas
* new function: dag.search
* new function: summary_dagRdag

OPEN ISSUES
* brute.search
- has trouble if there are no eligible adjustment sets to evaluate
  (e.g. only unknown variables, but allow.unknowns=FALSE)
* dag.draw
- for some reason, this sometimes has a problem because components
  of dag$arc strangely become lists instead of numeric
* dag.letter
- unknowns are not shown with adjustment marking
- adjustment marking is not described in documentation
* summary_dagRdag should become summary.dagRdag...
* helper functions should go internal...