Don't safeguard empty strings while reading#1223

ax3l merged 3 commits intoopenPMD:devopenPMD/openPMD-api:devfrom

franzpoeschel:workaround-no-safeguard-while-readingfranzpoeschel/openPMD-api:workaround-no-safeguard-while-readingCopy head branch name to clipboard