test for PDFLaTeX and update README

VIRTUALENV     = virtualenv

HAS_PYTHON3    = NO

HAS_VIRTUALENV = NO

HAS_PDFLATEX   = NO

ifeq ($(shell which python3 >/dev/null 2>&1; echo $$?), 0)

HAS_PYTHON3 = YES

HAS_VIRTUALENV = YES

endif

ifeq ($(shell which pdflatex >/dev/null 2>&1; echo $$?), 0)

HAS_PDFLATEX = YES

endif

SPHINXEXTRA = -j $(shell $(PYTHON) -c 'import multiprocessing;print(multiprocessing.cpu_count())')

.PHONY: help clean-all clean clean-spelling epub mobi rst html pdf spelling anchor_check style_check

	@echo "Conversion finished. The MOBI manual file is created."

pdf: $(ANCHORCHECK)

	@if [ "$(HAS_PDFLATEX)" == "NO" ] ; then echo "PDFLaTeX was not found! Please check README.md for further instructions" 1>&2; exit 1; fi

	@(\

		cd src/Developer; \

		pdflatex developer; \

	@( \

		$(VIRTUALENV) -p $(PYTHON) $(VENV); \

		. $(VENV)/bin/activate; \

		pip install --upgrade pip; \

		pip install Sphinx; \

		deactivate;\

	)

- hyperref

- hypcap

- times

- tabulary

- framed

- wrapfig

- upquote

- capt-of

- needspace

----------------

Installing prerequisites for epub build

| Currently available:           | Description                                    |

| ------------------------------ | ---------------------------------------------- |

| centos7.def                    | CentOS 7.x with EPEL enabled                   |

| centos7.def                    | CentOS 7.x with EPEL enabled, no LaTeX         |

| centos8.def                    | CentOS 8.x with EPEL enabled                   |

| fedora30_mingw.def             | Fedora 30 with MinGW cross-compiler toolchain  |

| ubuntu16.04.def                | Ubuntu 16.04LTS with default MPI == OpenMPI    |