Update VIC webste for VIC 4.2

[jhamman]

As part of releasing VIC 4.2, we need to update the public documentation. I can do the actual website updates but I will need some help from @tbohn on those issues that I am less familiar with. Below is a list of the issues requiring new or augmented documentation:

New Features and Options:

• Added partial vegetation cover (within each tile). #127 Partial vegetation cover - @tbohn
• Daily vegetation parameters from file #35 Non-climatological time-varying veg parameters - @tbohn
• Carbon Cycle #13 New forcing variables for carbon cycle - @tbohn
• Carbon Cycle #13 Simulation of photosynthesis - @tbohn
• Carbon Cycle #13 Simulation of soil carbon storage and fluxes - @tbohn
• Differences in energy fluxes between develop branch and VIC 4.1.2.l when FROZEN_SOIL=TRUE #118 Soil moisture content for half-space below bottom soil layer (SLAB_MOIST_FRACT) - @tbohn
• Better out-of-box behavior for soil temperature scheme #66 New frozen soil options - @tbohn

Removed or Depreciated Options:

• Remove DIST_PREC option #22 Removed the DIST_PRCP option - @jhamman
• Get rid of user_def.h #21 Removed user_def.h - @jhamman
• remove ARC_SOIL and SOIL_DIR from global.param.sample #120 Removed ARC_SOIL and SOIL_DIR options from global.param.sample - @jhamman
• Consider removing LOG_MATRIC option #65 Removed LOG_MATRIC option - @jhamman
• Remove EXCESS_ICE scheme #38 Removed EXCESS_ICE option - @jhamman
• SUN1999 albedo implementation in snow_utility.c #39 Removed SUN1999 albedo option - @jhamman
• Insufficient documentation for COMPUTE_TREELINE and JULY_TAVG_SUPPLIED #58 Require JULY_TAVG_SUPPLIED=TRUE when COMPUTE_TREELINE=TRUE - @jhamman

Improved Documentation:

• OUT_ROOTMOIST does not contain “Root zone soil moisture” #55 Definition of OUT_ROOTMOIST - @jhamman
• http://www.hydro.washington.edu/Lettenmaier/Models/VIC/FAQ/FAQ.shtml#11 #78 Actual Evaporation > Potential Evaporation - @tbohn
• Add license to repo #133 Source Code License - @jhamman
• Release Naming Conventions #49 Formalized release naming conventions - @jhamman

Feel free to add more to this list if I missed anything.

[bartnijssen]

Make change to existing web site. Then release and consider moving to sphinx. I do not want to delay 4.2 for anything other than code fixes.

[jhamman]

Ok, will do.

@tbohn - Do you have documentation for the items listed above. We need to make changes to the sample global parameter file as well to reflect these new options.

[tbohn]

Hi @jhamman, you can check off all of the boxes for new features, as well as the box for the EXCESS_ICE option. I can't check them off myself because I don't appear to have permission...

[jhamman]

We're all done here once https://github.com/UW-Hydro/VIC_website/pull/10 is merged.