Update ltp-document-3.0.md

./make change to make
Merge pull request #59 from ruoshui1126/patch-1

Update ltp-document-3.0.md
fix issue #60
input validity check
note error
examples/srl.cpp & srl
template_unittest & empty string check & srl example
Merge pull request #62 from ruoshui1126/gtest

template unittest & examples/srl & dll inpute empty check