changes to parallel tabs sections implementation:
- nParCir is now set using a parameter instead of using a record
- added some more divisions by nParCir
also cleaned up code a bit
added laminar flow implementation for tabs model
changed reynolds number upper limit in EmbeddedPipe from 2700 to 4000
split dp_nominal in embeddedPipe so that it can be read even when use_dp is false
simplifications to EmbeddedPipe model
cleaner implementation of heat transfer eqns
changes to embeddedpipe:
-correction pressure drop calculation
-added example - still need to add unit test
-removed separate thermal resistances and added them to convective resistance
-cleaned up code
-removed/integrated pretty much obsolete parameters
-moved most final parameters into protected section
correct the fluid mass in EmbeddedPipe.mo + minor changes
changed pressure drop calculation so that it correctly takes into account the parallel circuits
created a new pressure drop component for this purpose: ParallelFixedResistanceDpM
Merge branch 'issue81_parallelTabs' of github.com:open-ideas/IDEAS into issue81_parallelTabs

Conflicts:
	IDEAS/Fluid/HeatExchangers/RadiantSlab/EmbeddedPipe.mo
add to forgotten factor 1/nParCir for pressure loss calculation for non-homotopy case.
Merge pull request #82 from open-ideas/issue81_parallelTabs

changes to parallel tabs sections implementation: