Type II Supernova Spectral Diversity. I. Observations, Sample Characterization, and Spectral Line Evolution

project "Millennium Center for Supernova Science" of the Iniciativa Cientfica Milenio del Ministerio Economa, Fomento y Turismo de Chile P10-064-F Danish Agency for Science and Technology and Innovation EU/FP7-ERC grant 615929 VILLUM FONDEN 13261 NSF AST0306969 AST0908886 AST0607438 AST1008343 AST-1613472 AST-1613426 AST-1613455 project "Millennium Institute of Astrophysics (MAS)" of the Iniciativa Cientfica Milenio del Ministerio Economa, Fomento y Turismo de Chile IC120009