build program line object for REM statements
build program line object for numeric assignment statements
build program line object for GOTO, GOSUB and  RETURN statements
build program line object for CLEARSCRN and END statements
remove some deprecated tests
add tests for string expression object builder
build a useable string expression object from the 'parse object' array
build program line object for string assignment statements
build program line object for TAB statements
build program line object for PRINT and PRINTLN statements
build program line object for INPUT statements
build a boolean expression object from a slice of the parse array
build program line object for IF statements
catch an otherwise valid line as an error if it has extra characters at the end
start to build program line manager