Added three files to photosynthesis module

C3 Species.csv
C3 photomodel.r
Documentations.docx
helper to copy settings and remove any run info
forgot to add clean.settings.R to DESCRIPTION
simple script to create a clean pecan.xml
extracted plot code from web to visualization (redmine #1927)
export plot.netcdf
forgot extension of the plot.netcdf.R
more options to save an image
check before commit
fix to plots from webappp to use new visualization code.
need stringr for some functions
get.sample was failing with one-parameter distributions, such as the exponential
Merge pull request #97 from mdietze/master

get.sample was failing with one-parameter distributions
exported derive traits; added RPostgreSQL to PEcAn.DB suggests
added more flexibility to pecan.worldmap function
updated documentation, added logging, moved transform.nas to meta-analysis package PEcAn.MA (where it is used)
print all convergence diagnostics at end of MA; added meta-analysis diagnostic plots using ggmcmc if package is installed; exported pecan.ma
minor code cleaning and updates to documentation in PEcAn.MA module
merge
fixed error using ggmcmc