do not run align_pft examples. Closes #1978

[infotroph]

Plus minor typo fixes

Description

• wrapped align_pft examples in \dontrun -- The example is informative to human readers but needs a live bety connection, which may not be available when examples are run at package build time. Fixes Benchmark package checks fail #1978.
• Added unit test constructed from examples above.
• Typo fixes in variable names. These are minor-looking but potentially disastrous if I misunderstood -- please check carefully.
• Stopped excluding Benchmark from Travis package checks. This means Travis now runs make check on all PEcAn packages and completes phase 2 of Timeline for package checks in CI (+ list of current check errors) #1949.

Motivation and Context

Review Time Estimate

• Immediately
• Within one week
• When possible

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the CHANGELOG.md.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.