Update documentation of unit commitment fuel use to be more clear and parsimonious, correct errors where implementation drifted away from documentation, and fix broken links.

Implement support for a normalized input file parser for part load heat rates. Keep the old parser with the non-normalized (and probably obsolete) format to continue support for people who have written input files against it.
Update implementation of unit commitment fuel use parsers to be incrementally more legible and conforming to python style recommendations.

Author: josiahjohnston

examples/production_cost_models/spinning_and_quickstart_reserves/inputs/gen_part_load_heat_rates.csv

@@ -0,0 +1,5 @@
+GENERATION_PROJECT,gen_loading_level,gen_heat_rate_at_loading_level
+S-NG_CC,0.4,2.694069
+S-NG_CC,1,6.705
+S-NG_GT,0,0.1039
+S-NG_GT,1,10.39

examples/production_cost_models/spinning_reserves/inputs/gen_inc_heat_rates.csv

@@ -0,0 +1,5 @@
+GENERATION_PROJECT,gen_loading_level,gen_heat_rate_at_loading_level
+S-NG_CC,0.4,2.694069
+S-NG_CC,1,6.705
+S-NG_GT,0,0.1039
+S-NG_GT,1,10.39

examples/production_cost_models/spinning_reserves/inputs/gen_part_load_heat_rates.csv

@@ -0,0 +1,5 @@
+GENERATION_PROJECT,gen_loading_level,gen_heat_rate_at_loading_level
+S-NG_CC,0.4,2.694069
+S-NG_CC,1,6.705
+S-NG_GT,0,0.1039
+S-NG_GT,1,10.39

examples/production_cost_models/spinning_reserves_advanced/inputs/gen_inc_heat_rates.csv

@@ -0,0 +1,5 @@
+GENERATION_PROJECT,gen_loading_level,gen_heat_rate_at_loading_level
+S-NG_CC,0.4,2.694069
+S-NG_CC,1,6.705
+S-NG_GT,0,0.1039
+S-NG_GT,1,10.39

examples/production_cost_models/spinning_reserves_advanced/inputs/gen_part_load_heat_rates.csv

@@ -3,26 +3,26 @@
 
 """
 Defines model components to describe unit commitment of projects for the
-Switch model. This module is mutually exclusive with the
-operations.no_commit module which specifies simplified dispatch
-constraints. If you want to use this module directly in a list of switch
-modules (instead of including the package operations.unitcommit), you will also
-need to include the module operations.unitcommit.fuel_use.
+Switch model. This module is mutually exclusive with the operations.no_commit
+module which specifies simplified dispatch constraints. This module has a 
+post-requisite of switch_model.generators.core.commit.fuel_use.
 """
 from __future__ import division
 
 import os, itertools
 from pyomo.environ import *
 
 dependencies = (
-    'switch_model.timescales', 'switch_model.balancing.load_zones',
-    'switch_model.financials', 'switch_model.energy_sources.properties.properties',
-    'switch_model.generators.core.build', 'switch_model.generators.core.dispatch'
+    'switch_model.timescales', 
+    'switch_model.balancing.load_zones',
+    'switch_model.financials',
+    'switch_model.energy_sources.properties.properties',
+    'switch_model.generators.core.build',
+    'switch_model.generators.core.dispatch',
 )
 
 def define_components(mod):
     """
-
     Adds components to a Pyomo abstract model object to describe
     unit commitment for projects. Unless otherwise stated, all power
     capacity is specified in units of MW and all sets and parameters