Update phrases.R to remove character assessments

Replaced all character assessments such as 'You are amazing' with encouragement about the effort the learner is expending.
make swirl play nice with testit function from swirlify
from and to feature prototyped for test mode
complete first part of lesson when starting partway thru in test mode
fix testit() no args situation
check that 'to' is greater than 'from' in test mode
fix bug related to lesson cutoff
remove extraneous code
Merge pull request #170 from swirldev/fromto

Extend 'test' mode functionality to accommodate new swirlify features
add any_of_exprs() to AnswerTests docs
use capture.output to avoid double printing
Merge pull request #175 from swirldev/capture

Avoid double printing in safeEval()
first iteration of script feature working
implement attempts counter to prevent opening new script each attempt
Merge branch 'master' of https://github.com/sagevann/swirl into sagevann-master
make a few modifications to @sagevann's proposed changes
Merge branch 'sagevann-master'
fix typo in praise
Merge branch 'master' into script
update news and make a small tweak to welcome message