Add a truncate option to CONV().
Fixes to documentation and error IDs in @chebfun/conv.m.
Rename truncate to same (consistent with MATLAB) as suggested by AA.
Enabling plot of a complex function defined on unbounded domain.
enabling plot for three inputs defined on an unbounded domain.
Fixing documentation and calling sequences for FRED and VOLT.

Closes #1007.
Throw error when trying to discretize operators on unbnd domains.

This closes #1073.
1. Adding tests for #1120.
2. Leaving the determination of xlim for plot(f,g) and plot(f,g,h) to matlab itself. See #697 and #703.
Shuffle around test cases for plotting on unbounded domains.
Merge branch 'feature-conv-truncate' into development
Merge branch 'fix-unbndfun-plot' into development
Merge branch 'fix-FredVoltDocs' into development
Merge branch 'fix-unbdDomDiscrError' into development