updated blockreference

src/main/resources/com/ardublock/block/ardublock.xml

src/main/webapp/com/ardublock/reference/abs.html

src/main/webapp/com/ardublock/reference/and.html

...ain/webapp/com/ardublock/reference/code_comment_head.html

src/main/webapp/com/ardublock/reference/constrain.html

src/main/webapp/com/ardublock/reference/digital-high.html

src/main/webapp/com/ardublock/reference/digital-low.html

src/main/webapp/com/ardublock/reference/elseif.html

src/main/webapp/com/ardublock/reference/equal.html

src/main/webapp/com/ardublock/reference/false.html

src/main/webapp/com/ardublock/reference/glue_digital.html

src/main/webapp/com/ardublock/reference/glue_number.html

src/main/webapp/com/ardublock/reference/glue_string.html

src/main/webapp/com/ardublock/reference/greater.html

src/main/webapp/com/ardublock/reference/greater_equal.html

src/main/webapp/com/ardublock/reference/if.html

src/main/webapp/com/ardublock/reference/less.html

src/main/webapp/com/ardublock/reference/less_equal.html

...ebapp/com/ardublock/reference/local_variable_digital.html

...webapp/com/ardublock/reference/local_variable_number.html