Renaming to '*This()` and fixing documentation

Changes to be committed:
modified:   DESCRIPTION
modified:   NAMESPACE
modified:   NEWS.md
renamed:    R/getValue.r -> R/getThis.r
modified:   R/reactr.R
renamed:    R/setValue.r -> R/setThis.r
renamed:    R/setValue_bare.r -> R/setThis_bare.r
modified:   README.md
modified:   inst/examples/getBoilerplateCode.r
new file:   inst/examples/getThis.r
deleted:    inst/examples/getValue.r
renamed:    inst/examples/setValue.r -> inst/examples/setThis.r
renamed:    inst/examples/setValue_bare.r -> inst/examples/setThis_bare.r
modified:   inst/prof/prof_1.r
modified:   man/getBoilerplateCode-Reactr.BindingContractMonitored.S3-method.Rd
modified:   man/getBoilerplateCode-Reactr.BindingContractMonitoring.S3-method.Rd
modified:   man/getBoilerplateCode-Reactr.BindingContractMutual.S3-method.Rd
modified:   man/getBoilerplateCode.Rd
renamed:    man/getValue-character-environment-method.Rd -> man/getThis-character-environment-method.Rd
renamed:    man/getValue-character-missing-method.Rd -> man/getThis-character-missing-method.Rd
renamed:    man/getValue.Rd -> man/getThis.Rd
modified:   man/reactr.Rd
renamed:    man/setValue-character-ANY-environment-character-environment-call-method.Rd -> man/setThis-character-ANY-environment-character-environment-call-method.Rd
renamed:    man/setValue-character-ANY-environment-character-environment-function-method.Rd -> man/setThis-character-ANY-environment-character-environment-function-method.Rd
renamed:    man/setValue-character-ANY-environment-character-environment-missing-method.Rd -> man/setThis-character-ANY-environment-character-environment-missing-method.Rd
renamed:    man/setValue-character-ANY-environment-character-missing-call-method.Rd -> man/setThis-character-ANY-environment-character-missing-call-method.Rd
renamed:    man/setValue-character-ANY-environment-character-missing-function-method.Rd -> man/setThis-character-ANY-environment-character-missing-function-method.Rd
renamed:    man/setValue-character-ANY-environment-character-missing-missing-method.Rd -> man/setThis-character-ANY-environment-character-missing-missing-method.Rd
renamed:    man/setValue-character-ANY-environment-missing-environment-call-method.Rd -> man/setThis-character-ANY-environment-missing-environment-call-method.Rd
renamed:    man/setValue-character-ANY-environment-missing-environment-missing-method.Rd -> man/setThis-character-ANY-environment-missing-environment-missing-method.Rd
renamed:    man/setValue-character-ANY-environment-missing-missing-missing-method.Rd -> man/setThis-character-ANY-environment-missing-missing-missing-method.Rd
renamed:    man/setValue-character-ANY-missing-character-missing-call-method.Rd -> man/setThis-character-ANY-missing-character-missing-call-method.Rd
renamed:    man/setValue-character-ANY-missing-character-missing-function-method.Rd -> man/setThis-character-ANY-missing-character-missing-function-method.Rd
renamed:    man/setValue-character-ANY-missing-character-missing-missing-method.Rd -> man/setThis-character-ANY-missing-character-missing-missing-method.Rd
renamed:    man/setValue-character-ANY-missing-missing-missing-missing-method.Rd -> man/setThis-character-ANY-missing-missing-missing-missing-method.Rd
renamed:    man/setValue.Rd -> man/setThis.Rd
renamed:    man/setValue_bare.Rd -> man/setThis_bare.Rd
modified:   rapp/dev/example.r
modified:   rapp/dev/stackoverflow.R
new file:   tests/testthat/test-getThis-1.r
deleted:    tests/testthat/test-getValue-1.r
renamed:    tests/testthat/test-setValue-1.r -> tests/testthat/test-setThis-1.r
renamed:    tests/testthat/test-setValue-2.r -> tests/testthat/test-setThis-2.r
renamed:    tests/testthat/test-setValue-3.r -> tests/testthat/test-setThis-3.r
renamed:    tests/testthat/test-setValue-4.r -> tests/testthat/test-setThis-4.r
renamed:    tests/testthat/test-setValue_bare-1.r -> tests/testthat/test-setThis_bare-1.r
renamed:    tests/testthat/test-setValue_bare-2.r -> tests/testthat/test-setThis_bare-2.r
renamed:    tests/testthat/test-setValue_bare-3.r -> tests/testthat/test-setThis_bare-3.r
renamed:    tests/testthat/test-setValue_bare-4.r -> tests/testthat/test-setThis_bare-4.r