Increase test coverage to at least 85% for branches and 95% for statements about tcr

[akuanti]

--------------------|----------|----------|----------|----------|----------------|
File                |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
--------------------|----------|----------|----------|----------|----------------|
 contracts/         |    98.87 |    77.11 |    98.18 |    98.52 |                |
  PLCRVoting.sol    |     96.2 |    55.17 |    95.45 |    95.24 |102,103,105,370 |
  Parameterizer.sol |      100 |    84.09 |      100 |      100 |                |
  Registry.sol      |      100 |    92.19 |      100 |      100 |                |
--------------------|----------|----------|----------|----------|----------------|
All files           |    98.87 |    77.11 |    98.18 |    98.52 |                |
--------------------|----------|----------|----------|----------|----------------|

We do not quite reach 85% branch coverage in Parameterizer.sol due to several calls to token.transfer(), as well as some assertions.